Draftsman&#39;s triangle and protractor.



C. W. BARNABY.

DRAFTSMAN'S TRIANGLE AND PROTRACTOR.

APPLICATION FILED JUNE H, 1912- Pat'ented June 26, 1917.

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PM wkct amw mmrqim CHARLES w. BARNABYQ OF new YORK, N. Y.

DRAFTSMANS TRIANGLE AND PROTRACTOR.

Specification of Letters Patent. Patented June 26, 1917.

Application filed June 11, 1912. Serial No. 702,966.

To all whom it may concern:

Be it known that I, CHARLns N. BARNABY, a citizen of the United States, residing "in the first ward, borough of Richmond, county of Richmond, city of New York, and State of New York, have invented a new and useful Draftsmans Triangle and Protractor, of which the following is a specification.

My invention relates to improvements in draftsmens triangles in which are combined the features'of an adjustable triangle and adjustable protractor, or bevel-protractor; and the objects of my improvement are, first, to provide for quick and accurate adjustment of the device to either a 45 or a triangle, the two which are in general. use by draftsmen; second, to provide for the ready adjustment of the triangle to an angle of any required number of degrees and frac-- tion of a degree; and, third, to provide a protractor in which accurate adjustment to small fractions of a degree 1s easily obtained in a device which is of comparatively small andcompact form.

I attain these objects by the device illustrated in the accompanying drawing, in which Figure 1 is a perspective view of one form of my device; Figs. 2, 3, 4 are plan and sec tional views, respectively, of a preferred ap plication of my invention, and Figs/5, 6, 7 8, 9 are views representing various adjustments of the device shown in Fig.

Similar letters refer to similar parts throughout the several views.

The angle piece a comprises the main piece of the device, the segment I; comprises the movable member of the device, the periphery of its are surface being provided with a tongue 0 which engages with a groove in the concave edge of the main piece a, to which the'segment is accurately fitted. The segment is retained and locked to the main piece by means of the guard 7, which is dovetailed int-o the main piece, as shown in section Fig. i, and is provided with a flanged leg at its outer end which engages with the groove 9 in the segment. The surface it of the segment, between the groove 9 and are periphery, is depressed to clear the under surface of the guard f, which permits the segment to be moved to various positions with respect to the guard and the main piece. Upon this depressed surface, h, are also placed the graduations, thus protecting them fromwear. The surface '10 on the main piece is depressed on a bevel so that the edge adjacent to the periphery of the segment is on the same level as the surface hto facilitate accuracy of reading the graduations.

The guard 7", Figs. 2, 3, is controlled by springs p, p which are attached to the guard by means of screw 40,, the other end of the springs being attached, through screw m to the small plate 1', which is secured to the main piece-by the screws Z, Z. A slot 1" is cut through the mainpiece a to clear the springs p, p. i

Referring to Fig. 3, the springs 79, p are more curved before assemblingthan they appear in' the figure. In assembling the middle portion ofthe springs is pressed inward, which has a tendency to lengthen them, so that the screws 1%, n can be put in place. The pressure then being removed from the middle portion of the springs they have a tendency to take their original form of greater curvature, thus drawing'the screw it toward m and causing the guard f to draw the segment 6 tightly in contact with the main piece a. It is therefore obvious that in order to adjust the device all that is required is to grasp the main piece in one hand with the thumb on spring 72 and the index finger on p and press the springs'inward, which will force the screw it and guard f outward-and =release'the grip on the segment 6 so that it may be grasped by the other hand and moved to the desired position. The pressure of the thumb and finger then being removed from the springs the device is securely locked in the position to which it has been adjusted.

To facilitate adjustment, I prefer, in the application of my invention, to provide stops for the principal adjustments. In Figs. '2, 7, 8 the extended end cl of the segment is in contact with the part c of the main piece, the zero mark of the vernier being at the same time coincident with the 45 graduation on the protractor. Itis therefore obvious that all that is required to put the device in adjustment for use as a 45 triangle is to free the lock 7 by pressing the springs 79 p and throw d in contact with e. To get a quick adjustment to the 60 triangle position, all that is required is'to set the lower end (Z of'the segment to coincide with the part c of the main piece as shown in Fig. 5. When the segment is shifted as far as possible toward the right, at which? point the end of groove 9 comes in contact with the guard f, the device will be in the zero position,'as in Fig. 6, also in the position, Fig. 9.

The device as shown in Fig. 2 has two setsof figures and readings. When placed so that the edge a of the main piece is on a horizontal line, so that the figures 0 to 45 near edge a read right side up, the readings for the various adjustments are taken from the figures on the protractor and vernier which read approximately right side up from this point of view, which are figures 7c of the Vernier and figures 0 to 45 on the depressed surface h. In this position all angles from 0, or horizontal, as indicated in Fig. 6, to 45, as in Fig. 7 may be obtained. lVhen the device is in the position in which it is shown in Fig. 2, with the edge a on a horizontal line, so that the figures 45 to 90 near edge a read right side up, the readings are taken from; figures which are approximately right side up from this point of view, which are figures 7:: of the Vernier and figures 4:5 to 90 just to the left of groove 9. In this position all angles from 45 to 90 are obtained, as indicated by Figs. 8, 9. It is thus seen that all angles of the quadrant, from horizontal to perpendicular, may be obtained by the various adjustments from Fig. 6 to Fig. 9.

The vernier as shown in Fig. 2 reads to one-twelfth of a degree, or five minutes.

In bevel-protractors as constructed prior to my invention the fixed and the adjustable members of the device have either been, piv oted together by a bearing at their common center, or the outside, or main member encircles the inner member to the extent of considerably more than 180, the inner member being carried around through an almost or fully complete circle within the outer member so that the periphery of the inner member acts as a pivot to keep the inner member concentric with the outer member. In either case the device is much larger in comparison with the radius of the graduated are than is the case with the device of my invention.

In my invention, using only a comparatively short are and small segment considerably remote from the center, 00, Fig. 2, I get a much longer radius, y, for a given sized device than has been obtainable with those constructed prior to my invention. I am therefore enabled to graduate my device to a much smaller fraction of a degree without having the graduation lines too close together for satisfactory reading.

Fig. 1 illustrates the application of my invention in a simpler form in which the guard f of the other figures is dispensed with, the segmental and main pieces of the device being held in contact with each other by the tongue ,0 which is dovetailed into the groove of the other member for that purpose. The end extension d of the other figures is omitted on this device.

I do not limit myself to the details of 0011- struction herewith shown and described as various modifications in detail will be apparent to those familiar with devices of this character which do not fall outside the scope of my invention.

Having thus described my invention I claim:

1. A pivotless adjustable angle device comprising a segmental member, a second member provided with a non-encircling c011- cave edge adapted to engage the convex edge of said segmental member, a flat face of one of said members being provided. with a circular, depressed surface and a circular groove, and the other of said members be} ing provided with a recess radially located with respect to the arc of junction of the two members, and a guard member adapted to sweep along the circular depression and provided with an end flange to engage and traverse the circular groove in the one memher, said guard being secured in the radial recess in the other member, whereby the segmental member and the second member are maintained in close, adjustable relation with each other.

2. A pivotless angle device comprising a segmental member, a second member engaging with the convex surface of the segmental member and a retaining guard sunk flush with and secured in the face of one member and operating in a circular depression of the other member and at the same time engaging with a groove in said other member whereby the two members are maintained in adjustable engagement with each other.

3. A draftmans combination triangle and bevel-protractor comprising a segmental member with a circular, depressed, graduated surface in which is'placed a circular groove concentric with the convex edge of the member, a graduated, concave edge member adaptedto operatively engage the convex edge of the segment member and provided with a recess radially disposed in relation. to the arc of engagement of the two members, and a flanged end guard member, the flanged end engaging the circular groove in the segment member and the other end being secured in the radial recess in the concave edge member, whereby the segment and concave members are maintained in close adjustable relation with each other.

4. A draftmans adjustable triangle comprising a segmental member with a depressed surface along its convex edge and with a circular groove in said depression concentric with the convex edge of the segment, a concave member adapted to operatively engage the convex edge. ofthe segment member and provided with a recess radially disposed in relation to the arc of engagement of the two members, a guard member with a flanged end adapted to engage the groove in the segment member while the other end is adapted to adj ustably engage the radial recess in the concave member, and a locking means connecting the guard member, operatively, with the concave member, whereby the guard member may be adjusted in a radial direction in the recess in the concave member to tighten or release the grip of the flange on the end of the guard member against the concave edge of the circular groove in the segment member.

5. A draftsmans adjustable triangle comprising an angle member with a concave edge opposite to the angle of the member and a recess in one face and radial to said concave edge, a segmental member with a depressed surface along an arc of its convex edge and with a circular groove in said depression concentric with this convex edge and with one end of the chord edge of the segment extended beyond the arc edge and made of such shape as to come in contact with one end of the angle member when the chord edge of the segment member is at some certain angle with respect to an edge of the angle member and to complete the contour of the angle at that corner, and a guard member having a flanged end and adjustably fitted within the radial recess in the angle member and traversing the depressed surface of the segment member and engaging, through its end flange, the circular slot in said depressed surface.

6. In a draftsmans adjustable triangle, a segmental member having a circular slot, a second member provided with a concave edge and engaging operatively with said first member, and a guard attached to one member and having a flanged end engaging with the circular slot in the other member, the guard flange and end of slot being arranged to come in contact with each other to act as a stop to bring the triangle to a fixed angular position.

7. In an adjustable triangle consisting of a segmental member operatively connected with the concave edge of a right angle member, a projecting shoulder at one end of said segmental member arranged to come in contact with one extremity of said angle memher to bring the straight edge of the segmental member to rest at an angle of fortyfive degrees from each of the ninety degree edges of the right angle member, the other end of the right angle piece being finished in a straight line with the straight edge of the segmental piece when the latter is in a position giving angles of sixty and thirty degrees respectively with the two ninety degree edges of the right angle piece.

8. In a draftsmans triangle having a segmental member connected in a circularly adj ustable manner with a ninety degree angular member, a stop at one extreme of the movement of the segmental member to bring it at rest at a position in which its straight edge is at-an angle of forty-five degrees with the ninety degree edges of the angular member, a second stop at the other extreme of the adjustment of the segmental member to bring the straight edge of said member at rest when it reaches a position in which it is parallel with one of the ninety degree edges of the angular member, and a common flush edge condition of the straight edge of the segmental member and an extremity of the angular member when the straight edge of the segmental member is at an angle of sixty degrees with one of the ninety degree edges of the angular member.

9. A pivotless adjustable angle device comprising a segmental member, a second member provided with a non-encircling concave edge adapted to engage the convex edge of said segmental member, a flat face of one of said members being provided with a circular, depressed surface and a circular groove, and the other of said members being provided with a recess radially located with respect to the arc of junction of the two members, a guard member adapted to sweep along the circular depression and provided with an end flange to engage and traverse the circular groove in the one member, said guard being secured in the radial recess in the other member, and an elliptical spring connecting said guard member to the member in which it is recessed and adapted to act normally to draw said guard member radially into its recess to hold the segmental member in close contact with the second member, said elliptical spring being adapted, through pressure applied to its convex surface, to force said guard member radially outward of its recess to release its gripping action and permit the segment member to be adjusted to a new position relative to the second member.

10. In a device of the character described in which a member is adjustable relative to another member along their abutting edges, a locking device consisting of a locking element adjustably guided in one of said mem bers to move perpendicularly to the said abutting edges and carrying a jaw to engage a ridge carried by the other of, said members, said ridge being disposed parallel to said abutting edges. and an elliptical spring connecting said locking element with the member in which said locking element is guided so as to normally draw the relatively adjustable members into close contact along their abutting edges, said elliptical spring being adapted through pressure applied to its convex portion to release the grip of the locking element and thereby permit the relatively adjustable members to be adjusted to another relative position.

11. In an adjustable angle device, amember adjustably joined to a second member along their abutting edges, one member being provided With a guiding means perpendicular to said abutting edges and also being provided with an opening through said member adjacent to the inner extremity of said guiding means, the other member being provided With engaging means disposed parallel to said abutting edges, a locking element operating in the guiding means of the one member and adapted to engage the engaging means of the other member, and a pair of elliptical springs connecting the locking element with the member in Which said looking element is guided, said elliptical spring acting to normally hold the locking element in engagement with the engaging means of the other member and adapted to relieve said engagement upon application of pressure to the convex portion of one or both of said elliptical springs.

CHARLES W. BARNABY, Witnesses:

PAUL WHrrcoMB, C. L. RORER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

